Selective signaling system.



R. N. HILL. SELECTIVE SIGNALING SYSTEM. APPMOARION rum) MAR.21,1912.

l, 1 $3,288. Patented July 14, 1914.

W T/29.55% r UNITED STATES PATENT QFFIGE.

RALPH N. HILL, OF MONTCLAIR, NEW JERSEY, ASSIGNOR '10 WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y.-, A CORPORATION OF ILLINOIS.

SELECTIVE SIGNALING SYSTEM.

Specification of Letters Patent.

Patented July 14, 1914.

Application filed Hatch 21. 19%. Serial No. 665,244.

To all whom it m (13 concern:

Be it known that I, RALPH N. HKLL, citizen of the United States, residing at Montclair, in the county of Essex and State of New Jersey, have invented a certain new and useful Improvement in Selectrve Signaling Systems, of which the following is a full, clear, c ncise, and exact description.

Thisiinvention relates to an answer'back for signaling systems. and more particularly to an answer-back for party line signaling systems wherein the different stations are selectively signaled.

, The object of the invention is to provide an answer-back system which shall be simple, inexpensive and reliable in operation.

In the signaling system to which this invention is applicable, there is )rovided a telephone set comprising a telep lone transmitter in circuit with a local battery'and the primary of an induction coil the secondcry of which is adapted for connection with the line wires. 'Ihe answer-back signal is obtained by causing rapid changes in the resistance of theloca] circuit including the transn'iitter which will in turn induce a tone on the line to be heard atthecall initiating station. Thespecific means provided for obtaining this signal consists of an electromagnctically operated vibrator mechanically associated with the telephone transmitter, and having a circuit including the local battery of the transmitter which is closed in the operation of the semaphore or other visual signal.

The drawing is a circuit showing the wiring of apparatus in a semaphore signaling system embodying this invention.

In the drawing designates a despatchers or calling station and 0, 7 and 8 way stations all connected with line wires 10 and 11. Located at the (lespatchers or calling station 5 is a central battery 12 adapted to be alternately connected and disconnected with the line wires 10 and 11 through contacts 13 and 14 on an impulse relay 15. The'impulse relay 15 is in circuit with a local battery 16 and interrupting or transmitting key 17. Also connected with the line wires 10 l and 11 at the despatchers orcalling station is a telephone set comprising a receiver '18 bridged across the line wires in series with a condenser 19 and the secondary. of an induction' coil '20, and a transmitter 21 in' a local circuit with a battery 22 and the primar of the induction coil 20.

T o apparatus and circuits at each of the way stations 6, 7 and 8 are the same and as shown at station 6 and are as follows: Bridged. across the line wires 10 and 11 is a selector mechanism comprising electromagnets 25 and 26 controllin the operation of a bridge an electromagnet 30 across the line wires 10 and 11. The electroma net 30 when energized withdraws a dog 31. tom engagement with a; vertically movable rod 32'connected with a semaphore arm 33 permitting ger position. The lower end of the movable rod 32 is operatively connected with a clock train interrupting mechanism 39 which may be an ordinary district messenger-call box' and which when operated rotates a shaft carrying contact wheels 35 and 36 to close circuits through contact springs 37'and 88 as will hereinafter appear. Looated'at the way station is a telephone set comprising a receiver 45, a transmitter 46, induction coil 47, local battery 48, receiver switch hook 49 and condenser 50. In the talking and listening condition of the telephone set the transmitter 46 is in a local circuitclosed through a contact 51 of the receiver switch lid- 1:49 and including the local battery .48 and primary of the induction coil 47 inseries therewith. The receiver circuit will be from line wire 10' over conductor 52, conductor 53, the receiver 45, secondary of induction coil 47, contacts 51 and 54 of the receiver switch hook, conductor 55, conductorfi, condenser and conductor 57 to the otherlinc when.

The means through which the answerback signal is obtained are as follows: Mounted upon the back of the transmitter 46 is an electromagnetic vibrator 60 having an operating circuit including the local battery 48 and a normally closed contact 61 on'the receiver switch hook. The operation of the vibrator 60 agitates the granular carbon or other comminuted material in the transmit'- ter which causes a tone to be sent over the line through the same path as' the outgoin .voice currents which Wlll be heard in the r ceiver at the despatchers station. Following now the operation of the anrent paths thereof it will, he assumed ratchet wheel 27 which 0 oses contacts 29 to said arm to move into its horizontal or danswer-back mechanism and thefvarious curthe receiver 45 is on the switch book 49 and that the necessary number or character of current impulses have been sent to cause the closure of contacts 29'. This of course will cause the withdrawal of the dog 31 through the operation of the electromagnet 30 and operation of semaphore arm 33 and 'rod 32. As the rod 32 descends it causes the rotation of the shaft 40 and with it the interrupter wheels 35 and 36. \Vhen Contact is closed between wheel 35 and contactspring 37 an operating circuit is completed for the vibrator which may be traced as follows: from one side otbattery 48, conductor 65, conductor 66, windingpf vibrator 60, conductor 69, contact 61, conductor 70, conductor 71, contact spring 37, wheel 35,,shaft 40, a contact sprin 72 hearing thereon and conductor 73 to t e other side of battery 48. Current in this path eausesthe operation of the vibrator which in turn sets up i).- variation in a circuit through the transmitter 46 also closed through wheel 35 and contact 37 V and traced as follows: from one side of the battery 48, conductor 65, transmitter -46, conductor 75, primary of induction coil 47, conductor '71, contactsprin 37, wheel 35,

other side of battery 48. Thecurrentin this path is varied by the agitation of the gratin.

lar carbon of the transmitter button caused by the operation of the vibrator and induces a current on the line through the secfor this current will be as follows: from one side of the secondary of induction coil 47 through the winding of the receiver t5, con ductor 53, conductor 52, line conductor 10, receiver 18 at dcs'patchers stationfi, line conduetor ll, conductor 57, condenser 50, conductor 56, contact spring 38, interrupter wheel 36, shaft 40, wheel 35, contactspri'ng 37, conductor 71 to the other side of the secondary of the induction coil 47. The make and break of the Whe'el'fifland spring 38 in terrupts the tone/and thus produces a code answer-back.

It will be noted that the same battery is utilized for operating thevihrator 60 as is used to supply currentto the transmitter thus avoiding theme of extra cells at the way stations with consequent saving in installation and maintenance.

I claim:

1, In a signaling system the combination with a pair of line wires, of a signal-transmitting station connected therewith, a sigmil-receiving station connected with said line wires, a telephone transmitter at said signal-receiving station adapted to be opera iiveiy associated with said line wires, vibrating means mechanically connected wit-li'said transmitter, and means at said transmitting station for receiving a signal resulting from the operation of said vibrating means.

2. In a signaling system the combination with a pair of line wires, of a signal-trans mitting station connected therewith, a signalq'eceivingnstation connected therewith a telephone transmitter-unsold signal-receivat said transmitting station operatirely con- V 'nected with said line wires. shaft 40, spring 72 and con actor 7-3 to the In a selective signaling system the com- .bination with a pair of line wires baring a transmitting station and a way station connected therewith, a selective signaling device :at said waystation, a telephone set at said I :WH'YSURLIUII including a transmit-tor and a ondary of the induction e011 4?. The path local battery adapted to be operativcly as oelatedv with said-line wn'rs, an elven-munglicth: vibrator having a resonant mnru-ction with said transmitter, a cirrnitt'or said electroniagnelic vibrator including said local battery, circuit-closing nit-ans lhereforx'ontrolled by said selector. and rnal -receiring ,n'ieans at said transmitting station in circuit to receive a signal resulting from the operation of said i-lcctroinagnotie vibrator.

In Witness whereof, I hereunto subscribe my name this 16th day at March it. D. ,'l.9l".

1 RALPH HILL; i W itncsses:

G. M. Catu'msno, V. F. llorramn.

ing station adapted to be op'eiafiiicly-mssm elated with said line wires, an electromagnetic vibrator mechanically connected with I said transmitter, and signabreceiving means 

